2 ms·

I remember the days when Microsoft and Intel would host the "PCxx" spec (where xx was the last two digits of the year) and tell everyone what all the standards

I remember the days when Microsoft and Intel would host the "PCxx" spec (where xx was the last two digits of the year) and tell everyone what all the standards for desktop machines were going to be for the next few years. Those days are gone though. 12V rail PSUs are nice for a number of reasons but I always liked that you could feed your DC input from the AC side or a battery and have a "free" UPS at the same time. It is a bit tricky with a switching supply since you don't want to have the battery seeing 25Khz power outages as the switcher turns on and off but its very doable. With a little bit of instrumentation you could have the PC itself control charging and monitoring the battery itself so only a minimal amount of hardware needed to give every motherboard its own UPS.

effie 7y ago
I am very much interested in this, using DC power sources is the future. How do I go around adding a 12V DC power supply to the ordinary ATX computer? Can you find some links for this?
- ChuckMcM 7y ago
  Such supplies exist for some levels of power. Very popular in the MiniITX community where power levels are < 300W.[1]. There is also a wealth of material on developing DC to DC converters and a number of modules for the same. For a non-engineer putting something together I would look at DC-DC converter modules (see https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=dc%20to%20dc%20converter https://www.digikey.com/products/en/power-supplies-board-mou...) that provided the necessary power rails, at the power level that was required. Such a solution would not be compact and integrated like one that was designed from scratch to be used in this way, but would certainly work. I used one of the MiniITX supplies to power a system that is mounted in a box on a tree with a solar panel charging a deep cycle battery. It is the download/storage point for a number of wildlife cameras nearby. [1] https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/B00NB6U3TS https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/...
  - effie 7y ago
    Thanks, this is useful. I am thinking about building a UPS at home from batteries, so it can supply around 650W of DC power. I assume that using voltage of 12V on the supply side of the DC-DC converter would be too energy-inefficient for such high a power, so I'm thinking I'd better string such 12V batteries in series to get higher voltage, say 300 V. This should have minimal transmission losses, so I can lead this to my DC-DC converter via standard electric wires.
    - ChuckMcM 7y ago
      Most of the mid-range UPS systems that are rated at 650KVA or above will use dual 12V batteries for 24V driving an inverter. You can get 1kW inverters for RV's but they need thick (0 gage) wires connected to the battery. For "universal" battery power (and lots of gear in the market already) consider 48V power. That has been the standard at phone companies for decades so there is a lot of support for it. I once bid on a 10kW 48V inverter on eBay that had been removed from service at a phone company. It made (240V two phase power for telephone racks).

effie 7y ago

I am very much interested in this, using DC power sources is the future. How do I go around adding a 12V DC power supply to the ordinary ATX computer? Can you find some links for this?

ChuckMcM 7y ago
Such supplies exist for some levels of power. Very popular in the MiniITX community where power levels are < 300W.[1]. There is also a wealth of material on developing DC to DC converters and a number of modules for the same. For a non-engineer putting something together I would look at DC-DC converter modules (see https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=dc%20to%20dc%20converter https://www.digikey.com/products/en/power-supplies-board-mou...) that provided the necessary power rails, at the power level that was required. Such a solution would not be compact and integrated like one that was designed from scratch to be used in this way, but would certainly work. I used one of the MiniITX supplies to power a system that is mounted in a box on a tree with a solar panel charging a deep cycle battery. It is the download/storage point for a number of wildlife cameras nearby. [1] https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/B00NB6U3TS https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/...
- effie 7y ago
  Thanks, this is useful. I am thinking about building a UPS at home from batteries, so it can supply around 650W of DC power. I assume that using voltage of 12V on the supply side of the DC-DC converter would be too energy-inefficient for such high a power, so I'm thinking I'd better string such 12V batteries in series to get higher voltage, say 300 V. This should have minimal transmission losses, so I can lead this to my DC-DC converter via standard electric wires.
  - ChuckMcM 7y ago
    Most of the mid-range UPS systems that are rated at 650KVA or above will use dual 12V batteries for 24V driving an inverter. You can get 1kW inverters for RV's but they need thick (0 gage) wires connected to the battery. For "universal" battery power (and lots of gear in the market already) consider 48V power. That has been the standard at phone companies for decades so there is a lot of support for it. I once bid on a 10kW 48V inverter on eBay that had been removed from service at a phone company. It made (240V two phase power for telephone racks).